|Lower Potomac Group, Eastern Coastal Plain of Maryland, Delaware, and New Jersey
The lower Potomac confining unit is regionally continuous from North Carolina to New Jersey and generally ranges in thickness from 50 to 100 ft but exceeds 1,000 ft toward the mouth of Delaware Bay (Trapp, 1992). Vertical leakage generally ranges from 1 ' 10-8 to 1 ' 10-4 (ft/day) (Trapp, 1992). Pope and Gordon (1999) presented a map showing the leakage distribution of the lower Potomac confining unit across southeastern New Jersey, and this map is used for the GIS.
Pope, D. A., and Gordon, A. D., 1999, Simulation of ground-water flow and movement of the freshwater-saltwater interface in the New Jersey coastal plain: U.S. Geological Survey Water-Resources Investigations Report 98-4216, 159 p.
Trapp, H., Jr., and Meisler, H., 1992, The regional aquifer underlying the northern Atlantic coastal plain in parts of North Carolina, Virginia, Maryland, Delaware, New Jersey, and New York-summary: U.S. Geological Survey, Professional Paper 1404A, 33 p., 11 plates.